Template-Type: ReDIF-Article 1.0 Author-Name: J. Velíšek Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: P. Calta Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: C. Crews Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: S. Hasnip Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Author-Name: M. Doležal Author-Workplace-Name: Department of Food Chemistry and Analysis, Institute of Chemical Technology, Prague, Czech Republic Title: 3-Chloropropane-1,2-diol in models simulating processed foods: Precursors and agents causing its decomposition Abstract: Formation of 3-chloropropane-1,2-diol (3-MCPD) was studied in model mixtures consisting of sodium chloride and either glycerol or various lipids (phospholipids, monoacylglycerols, diacylglycerols, triacylglycerols) derived mainly from palmitic and oleic acids. The average amount of 3-MCPD formed from these precursors after 30 min of heating at 200°C was from 9.7 (lecithin), to 5.1 (diacylglycerols), 4.7 (glycerol), 3.1 (triacylglycerols), and 2.9 (monoacylglycerols) µmol/mol, respectively. The formation of 3-MCPD from glycerol (one of the major precursors) was also studied in the presence of glutathione, cysteine, disodium carbonate and sodium bicarbonate, i.e. compounds having the potential to decompose 3-MCPD or to prevent its formation. The compound the most active in preventing the formation of 3-MCPD was sodium bicarbonate followed by disodium carbonate, cysteine and glutathione. The addition of glutathione lowered the level of 3-MCPD produced from glycerol and NaCl to approximately 80%, of cysteine to 42%, of disodium carbonate to 14%, and of sodium bicarbonate to as little as 8% in comparison to samples with no additive. Keywords: chloropropanediols, 3-chloropropane-1, 2-diol, 3-monochloropropane-1, 3-MCPD, acylglycerols, phospholipids, glycerol, glutathione, cysteine, carbonates Journal: Czech Journal of Food Sciences Pages: 153-161 Volume: 21 Issue: 5 Year: 2003 DOI: 10.17221/3493-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3493-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200305-0001.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:5:id:3493-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: A. Syntsya Author-Workplace-Name: Chemistry, Institute of Chemical Technology, Prague, Czech Republic Author-Name: J. Čpíková Author-Workplace-Name: Chemistry, Institute of Chemical Technology, Prague, Czech Republic Author-Name: M. Marounek Author-Workplace-Name: Chemistry, Institute of Chemical Technology, Prague, Czech Republic Author-Name: P. Mlčochová Author-Workplace-Name: Chemistry, Institute of Chemical Technology, Prague, Czech Republic Author-Name: L. Sihelková Author-Workplace-Name: Chemistry, Institute of Chemical Technology, Prague, Czech Republic Author-Name: P. Blafková Author-Workplace-Name: Chemistry, Institute of Chemical Technology, Prague, Czech Republic Author-Name: M. Tkadlecová Author-Workplace-Name: Chemistry, Institute of Chemical Technology, Prague, Czech Republic Author-Name: J. Havlíček Author-Workplace-Name: Chemistry, Institute of Chemical Technology, Prague, Czech Republic Title: Preparation of N-alkylamides of highly methylated (HM) citrus pectin Abstract: N-Alkylamides of highly methylated (HM) citrus pectin (DM = 73%) were prepared using heterogeneous amino-de-alkoxylation (aminolysis) with five selected n-alkylamines. The reaction was carried out in N,N-dimethylformamide at 8°C (n-butylamine), 25°C (n-hexylamine), and 45°C (n-octylamine, n-dodecylamine and n-octadecylamine). All the derivatives were converted into acid forms by washing with acidic water-ethanol mixture. The products were analysed by organic elemental analysis, diffusion reflection FT-IR spectroscopy and by 13C CP/MAS NMR. Both FT-IR and NMR spectra indicate the presence of alkylamide substituents bound to pectin. The degrees of amidation (DA) of the derivatives and molar and mass reaction yields (Ymand Yn) were calculated based on the results of elemental analysis. The DA values of the N-alkylamides were 39-55% that corresponded to Ynof 54-75%. Keywords: HM citrus pectin, amino-de alkoxylation (aminolysis), N-alkylpectinamides Journal: Czech Journal of Food Sciences Pages: 162-166 Volume: 21 Issue: 5 Year: 2003 DOI: 10.17221/3494-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3494-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200305-0002.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:5:id:3494-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: D. Smělá Author-Workplace-Name: Department of Chemistry and Biochemistry and Author-Name: P. Pechová Author-Workplace-Name: Department of Chemistry and Biochemistry and Author-Name: T. Komprda Author-Workplace-Name: Department of Chemistry and Biochemistry and Author-Name: B. Klejdus Author-Workplace-Name: Department of Chemistry and Biochemistry and Author-Name: V. Kubáň Author-Workplace-Name: Department of Chemistry and Biochemistry and Title: Liquid chromatographic determination of biogenic amines in a meat product during fermentation and long-term storage Abstract: Liquid chromatographic procedures employing two derivatisation reagents, dansylchloride and o-phthaldialdehyde (OPA), were compared and applied for the determination of biogenic amines in meat products during fermentation and long-term storage. Both methods give similar results in terms of the detection limits, repeatability, recovery, and accuracy. Secondary amines (spermine and spermidine) do not react with o-phthaldialdehyde thus only their LC determination after derivatisation with dansylchloride is possible. Their contents during fermentation and/or long-term storage are nearly constant or slightly decrease, thus their determination in both cases is not necessary. LC procedure employing OPA derivatisation is faster, much simpler in terms of the pre-treatment of samples, and it can be fully automated using an intelligent auto sampler. Keywords: biogenic amines, polyamines, HPLC determination, food, dry fermented sausage, ripening, storage Journal: Czech Journal of Food Sciences Pages: 167-175 Volume: 21 Issue: 5 Year: 2003 DOI: 10.17221/3495-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3495-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200305-0003.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:5:id:3495-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: J. Pinkrová Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: B. Hubáčková Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: P. Kadlec Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: J. Příhoda Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: Z. Bubník Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Title: Changes of starch during microwave treatment of rice Abstract: The properties of rice after microwave irradiation were evaluated by means of amylograph and enzymic determination of the total and the damaged starch. The content of the total starch was not affected by the immediate energy output used for irradiation but that of the damaged starch increased with microwave energy absorbed and the temperature of treatment, mainly at the moisture of 30% and the temperature of 100°C. The results of damaged starch determination are in accordance with the amylographic readings of changes at maximum viscosity. Amylographic characteristics suggest minimal changes resulting in MW treatment of rice at moisture below 23%. Keywords: rice, starch, amylograph, microwave Journal: Czech Journal of Food Sciences Pages: 176-184 Volume: 21 Issue: 5 Year: 2003 DOI: 10.17221/3496-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3496-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200305-0004.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:5:id:3496-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: I. Šmídová Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology and Author-Name: J. Čopíková Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology and Author-Name: M. Maryška Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology and Author-Name: M.A. Coimbra Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology and Title: Crystals in hard candies Abstract: The main purpose of the contribution presented here is the study of the glassy state and the presence of crystals in hard candies. Hard candies are non-chocolate sweets usually made of sucrose and glucose or of maltose syrup. They can also be made of alditols, used in sugar-free hard candies. In hard candies, carbohydrates or alditols are in amorphous state. Crystallisation in the glassy state of hard candies occurs as a result of a bad formulation, processing or storage and can be detrimental to the product quality. Differential scanning calorimetry was used to determine the glass transition temperature Tg and the amount of crystals. Polarising microscopy was used to show the undesirable presence of crystals in samples of hard candies. The carbohydrates composition of the samples was determined by HPLC and the moisture content in each sample was evaluated by Karl Fisher method. Keywords: hard candy, the glass transition, crystallisation, differential scanning calorimetry, polarising microscopy Journal: Czech Journal of Food Sciences Pages: 185-191 Volume: 21 Issue: 5 Year: 2003 DOI: 10.17221/3497-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3497-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200305-0005.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:5:id:3497-CJFS